Migrate data from 6.x-1.5 to 8.x-2.x

Added ingredient and ingredient settings migrations.

Refactored the 1.x branch test code to use base classes since the 6.x and 7.x test classes were exactly the same apart from the fixture file that was imported.

Trying to fix the test errors that started popping up with the retests that I just did.

Hey, how about a patch that isn't empty?

The last patch had a bad fixture. It was complaining about not having the system module installed, so I copied the table row from the D7 fixture. The problem was that it didn't contain all of the same fields as the D6 table.

I refactored the Recipe tests in preparation for making the 6.x migration tests run off the same code as the 7.x tests.

I decided to commit the ingredient migration changes so that I don't have as much uncommitted code around. So here's one last test of those changes just for the sake of due diligence.

Renaming migrations in Ingredient necessitates a small change in Recipe.

I discovered that the changes I committed might have had some problems. So I reverted them.

Added the recipe migration.